An international team analyzed data from 262 clinical trials involving 100,000 people, which evaluated a total of 19 currently available obesity drugs, including GLP-1 analogs such as semaglutide and tirzepatide. Overall, the results indicate that, despite substantial weight loss, most of the drugs do not significantly improve quality of life, and few show cardiovascular benefits after one year of treatment. Furthermore, those that achieved greater weight loss were often associated with more side effects. The study is published in The BMJ.
Sexually transmitted variants of the Shigella sonnei bacterium spread more rapidly than other strains, according to a study published in The Lancet Infectious Diseases. This study of more than 3,500 samples collected in the United Kingdom between 2016 and 2021 also observed that strains resulting from sexual transmission were more resistant to the antibiotic azithromycin in men who have sex with men than in other patient groups. The bacterium S. sonnei causes an acute diarrheal infection called shigellosis; it is known to cause traveler’s diarrhea, and over the past two decades, cases have increased as a sexually transmitted disease among men who have sex with men (MSM).
Targeted marine cloud bleaching is a proposed geoengineering method to increase the amount of light reflected by clouds and reduce the heat reaching Earth. A US team has taken advantage of a natural experiment that generated this effect—through aerosols produced by the massive Australian bushfires of 2019 and 2020—to study the possibilities and risks of using it to modify an extreme weather event like El Niño. According to the models used in the study, its early application could weaken El Niño, but it could also have unintended consequences, such as altering the timing and increasing the magnitude of the subsequent La Niña event. The work is published in Science Advances.
Rising sea temperatures are promoting the spread of Vibrio vulnificus, the marine bacterium nicknamed the “carnivore,” which can cause serious infections. Last summer, the European Center for Disease Prevention and Control (ECDC) warned of an increased risk during the summer months, especially in the Baltic Sea. This bacterium has also been identified along the Spanish coast, but experts explain that swimming in the Mediterranean is safe for the general public, as the bacterium thrives in waters with lower salinity. Even so, they recommend that vulnerable individuals remain vigilant and avoid swimming if they have open wounds.
A Spanish study rules out men’s lifestyle habits as an explanation for geographical differences in semen quality. The findings, presented at the annual congress of the European Society of Human Reproduction and Embryology (ESHRE), the abstract of which is to be published today in the journal Human Reproduction, are based on data from 386 men who attended seven assisted reproduction centres across the country between June 2024 and December 2025. They answered questions about their lifestyle habits (physical activity, tobacco use, alcohol consumption, coffee intake, etc.), their place of residence and their body mass index, amongst other factors. Semen quality was higher among men from northern Spain, even though lifestyle habits were similar across all regions, suggesting that differences in quality may be due to exposure to environmental pollutants, says the lead author.
According to the findings of two clinical trials published in Annals of Internal Medicine, adults at high cardiometabolic risk who slept almost 80 minutes less per night for six weeks gained nearly half a kilogram on average and experienced an increase in waist circumference. The studies included a total of 95 participants, all of whom had a habitual sleep duration of at least seven hours per night. Sleep restriction was also associated with increased leptin levels, a hormone involved in regulating energy balance, and with greater sedentary time.